Tuesday, September 28, 2010

Wolves & Ecology

... when we exterminated wolves from Yellowstone in the early 1900s, killing every last one, we de-watered the land. That’s right -- no wolves eventually meant fewer streams, creeks, marshes, and springs across western landscapes like Yellowstone where wolves had once thrived.

The chain of effects went roughly like this: no wolves meant that many more elk crowded onto inviting river and stream banks where the grass is green and the livin’ easy. A growing population of fat elk, in no danger of being turned into prey, gnawed down willow and aspen seedlings before they could mature. Willows are both food and building material for beavers. As the willows declined, so did beaver populations. When beavers build dams and ponds, they create wetland habitats for countless bugs, amphibians, fish, birds, and plants, as well as slowing the flow of water and distributing it over broad areas. The consequences of their decline rippled across the land.

Meanwhile, as the land dried up, Yellowstone’s overgrazed riverbanks eroded. Life-giving river water receded, leaving those banks barren. Spawning beds for fish were silted over. Amphibians lost precious shade where they could have sheltered and hidden. Yellowstone’s web of life was fraying and becoming threadbare.

The unexpected relationship between absent wolves and absent water is just one example of how big, scary predators like grizzlies and mountain lions, often called “charismatic carnivores,” regulate their ecosystems from the top down.

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Today, wolves are thriving in Yellowstone. The 66 wolves trapped in Canada and released in Yellowstone and the Idaho wilderness in 1995-96 have generated more than 1,700 wolves. More than 200 wolf packs exist in the area today and the effect on the environment has been nothing short of astonishing.

There was one beaver colony in the park at the time wolves were reintroduced. Today, 12 colonies are busy storing water, evening out seasonal water flows, recharging springs, and creating habitat. Willow stands are robust again and the songbirds that nest in them are recovering. Creatures that scavenge wolf-kills for meat, including ravens, eagles, wolverines, and bears, have benefited. Wolves have pushed out and killed the coyotes that feed on pronghorn antelope, so pronghorn numbers are also up. Riverbanks are lush and shady again. With less competition from elk for grass, the bison in the park are doing better, too.

Elk are the sole species that has been diminished -- and that, after all, was the purpose of putting wolves back in the game in the first place. The elk population of Yellowstone is still larger than it was at its low point in the late 1960s, but there are fewer elk today than in recent decades. The decline has alarmed elk hunters and the local businesses that rely on their trade.

Worse yet, from the hunting point of view, elk behavior has changed dramatically. Instead of camping out on stream banks and overeating, they roam far more and in smaller numbers, browsing in brushy areas where there is more protective cover. Surviving elk are healthier, but leaner, warier, far more dispersed, and significantly harder to hunt. This further dismays those who had become accustomed to easy hunting and bigger animals.

A lively debate is underway among game wardens, guides, and wildlife biologists about just how far elk numbers have declined, what role drought and other non-wolf variables may be playing in that decline, and whether elk numbers will -- or even should -- rebound. State wildlife agencies that once fed hay to bountiful populations of elk to keep them from starving during harsh winters depend on hunting and fishing licenses to fill their coffers. Predictably enough, they have come down on the side of the frustrated big game hunters, who think the wolves have killed too many elk. Hunters have been a powerful force for conservation when habitat for birds and big game is at stake, but wolf reintroduction hits them right in the ol’ game bag, and on this issue they seem to be abandoning former conservation allies.

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In this regard, ecological literacy is not a side issue. It’s a prerequisite for survival. The articulation of reality is more primal than any strategy or policy. If greed is turning the Earth into a scorched planet of slums, ignorance is its enabler. Just as American farmers once realized that erosion follows ignorance and learned how to plow differently, just as most of us finally learned that rivers should not be used as toxic dumps, so today we must learn that environments have the equivalent of operating systems. Predation by large carnivores is written deep into the code of much of the American landscape. Today, a rancher who expects to do business in a predator-free landscape is no more reasonable than yesterday’s industrialist who expected to use the nearest river as a sewer. Living with wolves may be a challenging proposition, but it’s hardly impossible to do -- as folks in Minnesota or Canada can attest.

I tread a line between Chip Ward's "Mother Earth knows best" and the ill-informed eco-nuts who love pandas and baby seals and ignore ecological detail. My viewpoint is that nature is a complex of life that is indifferent to humans. We are part of the web and if we push the web too hard it will snap and we will pay a price. But the great biomass of the planet is at tiny lifeforms that we mostly ignore. Ants make up a mass as great as us and bacteria overwhelm us in total mass. We are not the masters of creation.

To be successful we have to be smarter about our real place in life. I've got nothing against humans having an outsize piece of life on earth. I like humans. But we do have to recognize that we don't "own" earth and that we can push ecosystems too hard. I'm not a "back to nature type". I have nothing against humans reshaping vast tracts. On the other hand, I enjoy wild vistas of "untouched" nature, so I'm eager to save these. I'm a middle-of-the-road type. We shouldn't feel we sit in the catbird seat and we shouldn't picture ourselves as the bogey man. We have a role to play. We just have to remember to keep our activities in context.